In recent years, the popularity of white gold has steadily increased, resulting in a corresponding increase in the demand for white gold jewelry, particularly in Japan and China. Because it is inexpensive relative to platinum, white gold is particularly popular because the public cannot readily distinguish white gold jewelry from platinum jewelry. In other words, white gold jewelry is capable of maintaining the aura and exclusivity of platinum jewelry, at a substantial reduction in cost to the wearer.
Many jewelry manufacturers are capable of making jewelry from white gold. Indeed, because white gold exhibits better handling characteristics and a lower melting temperature than platinum, white gold jewelry is generally easier to manufacture than platinum jewelry.
Many different white gold alloy compositions are known in the art. These alloys generally comprise gold and at least one additional element, such as nickel, silver, platinum or palladium. Additional mixing elements, e.g., copper, may be used to round out the composition.
The addition of nickel to white gold gives the alloy a “whiter” base color at little cost. However, the addition of nickel increases the brittleness of the alloy, and may cause certain wearers to experience an allergic reaction.
Silver is the whitest of the metals, and unlike nickel, does not cause allergic reactions when included in white gold compositions. However, silver is relatively expensive and oxidizes upon exposure to air. Further, white gold alloys containing silver may be prone to tarnishing over time.
The addition of a combination of silver and nickel to white gold is also known. In these alloys, the relative content of silver and nickel is optimized to maximize the benefits and minimize the detriments of each element.
Platinum and/or palladium may also be added to white gold. However, due to their high cost, which may be more than twice that of gold, the inclusion of these elements into white gold is generally not economically feasible. This is particularly true if the resulting alloy is to be marketed as a white gold, which cannot command the same high price as platinum.
Due to the natural yellow color of gold, white gold alloys are not truly “white” in color. Depending on the composition of the alloy, the color of white gold may range from white with a slightly green tint to a white with a slightly yellow tint. This is true of all gold-based white gold jewelry, ranging from 10 karat white gold to 18 karat white gold.
Further, white gold alloys are also susceptible to corrosion, which can diminish the white color of finished articles, e.g., jewelry, manufactured from these alloys. To protect against such corrosion, articles manufactured from white gold are typically coated or plated with a layer of rhodium. While rhodium is a corrosion resistant and highly reflective white metal, it is more expensive than platinum. Thus, to be economically feasible, only very thin layers of rhodium are utilized. As a result, the layer of rhodium wears off gradually during normal use of the article, thereby exposing the underlying white gold alloy and its corresponding greenish or yellowish tint. To restore the article to a white color, rhodium must be re-plated/coated on the article. In the case of white gold jewelry this re-coating is generally necessary every six to eighteen months, assuming normal use and depending on the thickness of the rhodium layer.
While there are many ways to make white gold jewelry, the defining characteristic is that it contains relatively large amounts of gold. Gold is expensive, particularly in recent years. This high cost is a disadvantage, particularly in the case of gold jewelry, where gold may represent 80% or more of the finished product.